The use of air filters for filtering intake air entering engines, such as gasoline and diesel powered internal combustion engines, for subsequent combination is well known. Such known air filters generally include an air filter element comprising a paper and/or foam filtering medium. The filter element is attached to a housing that is mounted to an intake system of an engine intake system in a manner enabling filtering of intake air passed through the housing to the engine.
Conventional air filter housings typically includes an air intake opening in air flow communication with fresh air, an air outlet opening in air flow communication with the engine intake system, and the air filter element is interposed between the two openings. The air filter element is typically annular in shape, and is mounted in the air filter housing by a releasible attachment that passes through the air filter housing and that is attached to the engine.
Many conventional air filter housings are constructed to enclose the air filter element for the purpose of reducing the noise, i.e., silencing, associated with the air being passed through the air filer during operation of the engine. Additionally, the housing may be configured to direct warm air to the air filter and subsequently into the intake system when the engine is in a cold state, and direct ambient temperature to the air filter and subsequently to the intake system when the engine is warmed up.
While the use of such conventional air filter housings are somewhat effective in silencing the noise associated with the air passing through air filters, a problem known to exist with such conventional air filter housing is that they tend to restrict or reduce the overall flow of air to the air filter, thereby operating to reduce the overall air intake efficiency of the engine. Additionally, the use of such conventional air filter housings may not be practical in engine fitment applications having only limited space.
It is, therefore, desired that an air filter be constructed in such a manner that avoids the need to use conventional air filter housing for the purpose of providing an effective level of noise reduction, suppression, or silencing. It is also desired that such air filter be constructed in a manner that provides an improved level of air flow therethrough when compared to air filters enclosed in conventional air filter housings. It is further desired that such air filter be constructed and configured in a manner that facilitates use with engine applications having tight spatial constraints.